To expand on Barry’s answer - You can only set the broadcaster whitelist while the extension version is in ‘local test’. If you’re already in review you’ll have to cancel the review, add those channels to your whitelist, do the hosted test, then submit for review again. Then when you want to make the extension public, you’ll have to make a new version of the extension, remove all channels from the whitelist, and then go through the review process again. I think that would serve your purpose nicely.